1. Field of the Invention
The present invention relates generally to data transfer and, more particularly, to data transmission via a cable modem system.
2. Description of Related Art
Conventional cable modem systems include a cable modem termination system (CMTS) connected to one or more cable modems via a coaxial cable. The CMTS communicates with the cable modems via a radio frequency (RF) interface and provides packet forwarding functions via a network side interface. Separate frequency bands are used for upstream and downstream communication on the coaxial cable. For example, the upstream communication may take place on communication channels within the 5-42 MHz frequency band and the downstream communication may take place on communication channels within the 88-860 MHz frequency band.
One or more upstream communication channels may be bundled with one or more downstream communication channels to form a Media Access Control (MAC) domain. The MAC domain provides a broadcast network impression, such that a packet sent on an upstream channel may be broadcast to all of the cable modems connected to the downstream channel. The CMTS can have one or more MAC domains, where each of the MAC domains may be associated with one or more cable modems.
Data-Over-Cable Service Interface Specification (DOCSIS) is the standard for cable modem systems throughout the world. DOCSIS dictates that service identifiers be assigned to the cable modems by the CMTS. Each cable modem is assigned a different one of the service identifiers. As a result, there is a limit on the number of cable modems that can connect to the CMTS. This limit is based on the number of available service identifiers. In existing systems, there are approximately 8,000 different service identifiers, resulting in approximately 8,000 different cable modems that can connect to the CMTS.
In an embedded DOCSIS environment where there are devices that do not require large amounts of data to be exchanged, the 8,000 limit on the number of cable modems is inadequate.
As a result, there is a need for systems and methods for increasing the number of cable modems that may connect to a CMTS.